This thesis investigates the contributions of specific phonetic variables in the speech of native Korean L2 English speakers to perceptions of accentedness clarity. By correlating listeners' attitudinal responses with speakers' phonetic productions, I determine which phonetic variables contribute to a listener's perception of a speaker as accented, as well as their perception of the speaker's clarity. Although there exists a body of research in linguistics and in other fields on listener attitudes toward Korean-accented English and other varieties of Asian-accented English (Gluszek & Dovidio, 2010; Lindemann, 2003; Cargile, 1997), little research has been done on the phonetics of Korean-accented English. Lindemann (2003) studied listener attitudes toward Korean-accented English, but while some common features of Korean-accented English were discussed, no phonetic analysis was performed. Although the phonetic features of a Korean accent are generally known, there has been no phonetic analysis of these features and no research into how precisely they correlate with listeners' perceptions of accent. This study consists of two parts: a phonetic analysis of Korean-accented English productions, and an attitudes study of listener responses to those productions. Five speakers were recorded reading short passages: two native speakers of Korean who learned English after the end of the critical period; two bilingual speakers of Korean and English who acquired both languages within the critical period; and one monolingual native speaker of English. Seven phonetic variables were examined: 1. Degree of /a/ backing 2. Production of /o/ as monophthongal 3. Production of /u/ as monophthongal 4. Confusion of /r/ versus /l/ 5. Production of /ð/ as a stop 6. Voice onset time (VOT) of word-initial voiceless stops /p/, /t/, and /k/ 7. Overlap of /i/ and /ɪ/ 20 native English speakers listened to the recorded passages and completed an attitudes survey. Phonetic analysis indicated that the native Korean L2 English speaking subjects differed from the native English speaking subjects in their productions of /a/, /r/ and /l/, /ð/, word-initial voiceless stop VOT, and overlap of /i/ and /ɪ/. All of these features were correlated with increased perception of the speaker as accented. However, only /t/ VOT and monophthongization of /o/ correlated with perceptions of clarity, and /t/ VOT was the only variable correlated with both accentedness and clarity scores. I also found no correlation between listeners' ratings of speakers' accentedness and ratings of clarity, indicating that a foreign accent does not necessarily cause listeners to feel a speaker is less clear. This study takes steps toward filling the gap in existing research not only on the phonetics of Korean-accented English but also on attitudes toward Korean-accented English by drawing connections between specific phonetic features and listener attitudes.